Signaling system



May 5, 1925. 1,536,764

0. E. BUCKLEY SIGNALING SYSTEM 'd'n 27, 1919 F118 ec hvenfor: O/ivekE/bWoIf/I Buck/49y y zdwaw, A1734 till ' and State of New Jersey,

increases, the amount Patented May 5, 1925.

UNITED STATES PATENT oFFicE.

NEW JERSEY, ASSIGNOR '10 WESTERN ELEC- NEW YORK, N. Y., A CORPORATION 01NEW I SIGNALING SYSTEM.

Applicationfiled December 27, 1919. Serial N0. 347,773.

To all whom it may concern:

Be it known that I, OLIVER ELLSWORTH BUCKLEY, a citizen of the- UnitedStates, residing at Maplewood, in the county of Essex have inventedcertain new and useful Improvements in Signaling Systems, of which thefollowing is a full, clear, concise, and exact description.

This invention relates to telegraph systems and more particularly tosubmarine cable telegraph systems. Its principal object is the provisionofa relay arrangement which will introduce in the transmission ofsignals none of the difliculties commonly introduced by pole changingtransmitting relays when operated at high speeds.

In some types of telegraph systems, notably submarine cable systems itis necessary to introduce a pole-changing relay between the sending keyand the signaling conductor, it being impracticable to employ theprimary transmitting device for impressing signal impulses directly uponthe cable on 210- count of the excessive sparking which would occur atthe delicate contact points of the transmitter when breaking therelatively large currents "necessary for signaling through the cable.

polar relay is quite satisfactory. Any relay of the electromagnetic typeproduces a cer* tain amount of distortion at the beginning and end ofeach signal impulse, due to the chattering of the relay contacts. Forordinary slow speed signaling this ditliculty is not seriouslyobjectionable because the distorted portion represents but a smallpercentage of the total signal interval. \Vhen attempts are made toincrease the speed of signaling this difliculty becomes more serious inthat the ratio of the distorted portion to the undistorted portion ofthe signal impulses increases as the speed of signaling oi'energytransmitted during a signaling period, and consequently the amplitudesof the received signal, are thus reduced. This contacts "furthermoregreatly increases the disturbances due to slight inequalities out duplexbalance where duplex operation is used. 1

This invention provides a sending relay for telegraph systems which, sofar as the transmitting apparatus itself is concerned, imposes nolimitations on the speed at which For ordinary slow' speed signaling thewell known electromagnetic tube 6, said chattering of therelaytelegraphic or other signaling impulses may be transmitted. Theinvention makes use of a three electrode electric discharge device suchas the well known audion or thermionic relay operating by pure electrondischarge or similar. three element tubes operating with; ionized gas,the potential of the grid or control element of the device beingregulated by a transmitting key.

A better understanding of theinvention may be had from the followingdescription when taken in conjunction with the accompanying drawing inwhich Figure 1 shows a simplified arrangement for using a vacuum tubedevice as a relay in the transmission of direct current telegraphicsignals. F igure 2 is a modification of Fig. 1 arranged for groundingthe line between impulses. Fig. 3 is a modification of Fig. 2' in whichspace current normally flows through the tube. Fig. 4 shows analternative arrangement to that shown in Fig. 3. Fig. 5 shows analternative arrangement for transmitting signals of positive andnegative impulses such as are commonly used in cable telegra phy, whileFig. 6 shows a more symmetrical circuit arrangement using two electric.discharge devices or vacuum tubes for the transmitting of signals ofpositive and negative polarity.

Referring now to the drawing and especially to Fig. 1, there is shown aline conductor 4, having the distant end thereof grounded through a.suitable receiving apparatus (not shown) and the other and con: nectedwith the output circuit of the vacuum, output circuit comprising theheated cathode 5, the anode'or plate electrode 8 and the groundedbattery 9. A leakage path between the plate electrode 8 and the gridelectrode 7 is established through the resistance 10 having one terminalthereof connected with the plate electrode 8, the otherterminal beingconnected with the grid electrode 7 There is also connected with thegrid electrode '8' a source of potential 12, the positive terminal ofwhich is connected with the heated filament 5. The application of thissource of potential to the grid electrode thereby changes the polarityof the charge on this electrode with respect to the heated filament .5and reduces the space current to zero. When the source of potential 12is removed from the grid electrode the potential oi that electrode ismade positive by the battery 9 acting through the resistance 10, therebyreducing the internal resistance of the tube to the flow of current andpermitting current to flow through the tube to the line 4. There isprovided in circuit with the source of potential 12 and the gridelectrode 7 a key 11 which is for the purpose of controlling theapplication of this source to-the grid electrode and in consequence thecurrent in the output circuit of the tube 6. The impulses composing thevarious signals as impressed on the line are therefore controlled by thekey 11. Thus when it is desired to transmit signals over the line, thekey 11 would be depressed for disconnecting the source of potential 12.

This thereby renders the tube. operative andimpresses upon the line animpulse, the duration of which depends upon the length of time duringwhich this key is depressed.

The modification shown in Fig. 2 is substantially the same-aas that ofFig. 1 with the exception that the line is grounded through theresistance element 13. This ground is for the purpose of forming a pathfor discharging the line between signal impulses. The resistance element13, which, as noted, is connected in parallel with the plate electrode 8and the heated filament '5 of the tube 6 serves to regulate theintensity of the impulses applied to the line. In this case, as in theprevious one, the tube is normally inoperative and no current flows tothe line, but upon the depression of the key 11 the source of potential12 is disconnected from the grid electrode 7 and a potential is appliedto the line through the resistance 13. This resistance, thereby, servesto control the intensity of the impulses applied to the line and alsoserves to drain the charge from the line between signal impulses.

In Fig. 3 there is shown another embodiment of the invention in whichcase the source of potential 9 is normally disconnected from the gridelectrode 7. Inasmuch as the source of potential 12 is permanentlyconnected with the grid electrode 7 through the resistance 14, thiselectrode will thus be so charged with respect to the heated filament 5that space current cannot flow between the electrodes, and the line 15is normally discharged through the resistance 13. The key 11 upon beingdepressed connects with the grid-electrode 7 a source of potential 9through the resistance 16, and if the resistances 14 and 16 are properlyadjusted with reference to the sources of potential 12 and 9respectively the potential of the grid electrode 7 will thereby beestablished at such a value asto permit the desired signaling current tobe applied to the line. In this wayimpulses ofdifierent duration may beimpressed on the line 15 to represent dots and dashes.

Referring now to Fig. 4 and the particular embodiment illustratedtherein, and which is considered as a modification of the arrangementshown in Fig. 3, the key 11 controls the application ofboth of thesources of potential 9 and 12 respectively to the grid electrode 7. Thesource of potential 12 is normally connected with the grid electrode 7through the key 11, and thus charges this electrode negatively withrespect to the heated filament 5 and no space current will flow betweenthe filament 5 and plate 8. When the key 11 is depressed the source ofpoten tial 12 is disconnected from the grid electrode and the source 9connected thereto. The connection of this source of potential with thegrid electrode changes the charge thereon from negative to positive withrespect to the heated filament 5 and permits space current to flowthrough the tube to apply to the line a definite potential.

It is thus seen that the signaling is effected by means of the key 11and if it is desired to send impulses of various characters the key 11will be actuated for applyingcurrent to the line in accordance with thecharacter to be transmitted. The line is, however, grounded between thesignal impulses through the resistance 19 which provides a dischargepath for the current in the conductor 17 at the instant the key 11.isreleased.

In submarine cable signaling the various characters are generally formedof positive and negative impulses, and in Fig. 5 there is shown anembodiment whereby such signals may be transmitted over a signalingconductor. In this figure there is shown a portion of the cable 18having a conductor 22 connected to the vacuum tube 6 and the resistance13 through the condenser 23. The condenser 23 is the common'sendingcondenser well known to those skilled in the art. Its purpose is toreduce the distortion. of the signal impulses received at the distantend. The resistance 24 is equipped with three movable contact points 25,26 and 27. The batteries 9 and 12 are connected with the grid electrode7 through portions of the resistance 24 allowing current to flow throughthe resistance QAtherebyestablishing a potential gradient along thatresistance. The point 26 is so adjust-ed that a definite space currentwill flow through-the vacuum tube, thereby establishing a normalpotential difference between the terminals of the resistance 13. Thetongue or contact maker 28, which may form a part of an automatictransmitting apparatus, 'is adapted to be moved either to the left orright for the purpose of including with or excluding from the gridelectrode a portion of the resistance 2%. Contact makers of automatictransmitters do not have the tendencyto chatter which is present in theordinary transmitting polecontact member 25. This short-circuits aportion of the resistance 24 and connects the source of potential 9 withthe grid electrode 7 through the remainderwof this resistance andconsequently increases the spacecurrent through the tube 6 and increasesthe potential applied to the terminals of the condenser23. The sendingof impulses of negative polarity is accomplished in the same mannerexcept that the tongue 28 is moved to the left for engaging the contactmember 27. This connects the battery 12 with the grid electrode 7through a smaller portion of the resistance 24 than was in the previouscase. In this way the grid electrode 7 is charged more negatively withrespect to the heated filament 5 and thereby impresses upon the line 22an impulse of negative polarity. The

positive and negative impulses can be made to possess the same amount ofenergy by properly adjusting the contact members 25 and 27 on theresistance 24.

It is thus seen that a vacuum tube is not only adapted for use in thetransmission of dots and dashes,. but may also be employed for thepurpose-0f transmitting characters composed of positive and negativeimpulses.

Referring now to Fig. '6 there is shown a symmetricalcircuit arrangementcomprising two-electric discharge devices or vacuum tubes of the audiontype. such as 29 and 30. These devices as before are provided with theusual electrodes designated by the numerals 5, 7 and 8. The gridelectrodes 7 of these tubes are connected with the battery 31 throughthehigh resistance units 32 and 33 respectively, and are each therebygiven a negative charge sufiicient to reduce th space current to zero.

When the key 34 is moved to make contact with the point 35, the positivepole of battery 38 is connected by way of resistance 37 .to the grid 7of the vacuum tube 29. The potentials of-the batteries 31 and 38 and thevalues of resistances 32 and 37 are'so chosen that under this conditionthe potential of the grid 7 with reference to the filament 5 will bemade positive, that is the positive potential applied by the battery 38more than overcomes the negative potential applied from the battery 31and permits cur-.

rent to How in the output circuitof thev ac-z uum tube 29 from battery38 through I'ESISiZ" ance 41 in the direction of the arrow,

through the vacuum tube 29 from the plate 8 to the filament 5 and backto the other pole of battery 38. This flow of current through theresistance 41 gives the line conductor 42 a positive potential withrespect to ground and causes a positive impulse to flow toline.

When the key 34 is moved into contact with the point 36, the gridelectrode 7 of the vacuum tube 30 is made positive with res I ct to itsfilament 5 and current flows t rough the resistance 40 in the outputcircuit of the vacuum tube 30 in the direction of the arrow. This flowof current in the resistance 40 gives the line conductor '42 a negativepotential with respect to ground and consequently a negative impulseflows to the conductor. In the intermediate'position of the key 34, asshown in the drawing, the line conductor 42 is grounded through theresistances 41 and 40 so that any accumulated charges on the cableconductor can be drained off to ground. It is desirable that theresistances 32 and 33 be fairly high so that the circuit from battery 38through key 34, contact 35, resistance 37, resistance 32, battery 31,filament 5 back to battery 38, or'the corresponding circuit through theresistances 39 and 33, will have a minimum' shunting efl'ect on thecurrent flowing through the output circuit of the vacuum tube 29 or thevacuum tube 30 as the case may be. It is thus seenthat the arrangementin Fig. 6 is well adapted to send symmetrical positive and negativeimpulses at high speed over a cable conductor.

What is claimed. is: v

p 1. Terminal signaling apparatus for a cable or line for impressingupon said cable or line at any instant potential of one of at least twooperating values whereby signaling impulses of either polarity and inany desired sequence may be transmitted, said apparatus comprising thecombination with a local source of direct signaling potential, of highimpedance space discharge means in circuit with said source, controlmeans for said space discharge means, circuit making and breakin meansin circuit with said control means or directly associating saidsignaling potential with said control means, and means including saidcircuit making and breaking means for impressing at any instant uponsaid control means potential of one of at least two o crating values.

\ 2. Terminal signaling apparatus for a cable or line for impressingupon said cable or line at any instant potential of one of at least twooperating values whereby signaling impulses of either polarity and inany desired sequence may be transmitted,

said apparatus comprising the combination .space discharge means,circuit making and &

breaking means in circuit with said control means having two fixedcontacts, and means including said circuit making and breaking means forimpressing at any instant upon said control means potential of one of atleast two operating values, the said two last-mentioned values ofoperating potential being applied when the circuit is completed throughsaid fixed'co'ntacts respectively.

3. Terminal signaling apparatus for .a cable or line for impressing uponsaid cable or line at any instant one of three operating potentialvalues whereby signaling impulses of either polarity and in any desiredsequence may be transmitted, said apparatus comprising a local source ofdirect potential, high impedance space discharge means in circuit withsaid source, control means for said discharge means, circuit making andbreaking means in circuit with said control means, and means associateddirectly with said circuit makingand breaking means, and including asecond local source of potential for impressing upon said control meansat any instant one of three operating potential values.

4:. Terminal apparatus for a cable or line having large distributedelectrostatic capacity for impressing upon said cable or line at anyinstant one of at least two operating potential values whereby signalingwaves of either polarity and in any desired sequence may be transmitted,said apparatus comprising a local. source of direct potential, a highimpedance space discharge means in circuit with said source, a controlmeans for said discharge means, circuit making and breaking means incircuit with said control means, and means associated with said circuitmaking andbreaking means, and including a second local source ofpotential, for impressing upon said control means at any instant one ofat least two operating potential values.

5. The combination with a cable or line, of a local source of signalingdirect potential, space discharge means in circuit with said source,meansfor controlling the impedance of said space discharge means, asignaling key for controlling said space discharge controlling means andhaving at least two operating positions in one of which no current willflow through said space discharge means and in the other of which signalimpulses will be impressed upon said line or' cable, and means havingsubstantially no reactance at signaling frequencies for associating saidsource of potential with said cable orline, whereby the signalingimpulses impressed thereon are substantially rectangular in form.

6. In a high speed submarine cable system, the combination witha cable,of means for transmitting signals at such high speed that the chatterproduced by the tongue of the pole changing relay ordinarly employed forcable transmission would introduce a high frequency disturbance of aprohibitive value, a space discharge relay at the transmitter in placeof said ordinary pole changing relay, said space discharge relaycomprising an anode, a cathode and a control element, a local source ofsignaling potential controlled by said space discharge relay, means forassociating said source with said cable having negligible reactance atsignaling frequencies, and a signaling key at the transmitter associatedwith said control element and having at least two operating positionswhereby substantially rectangular signaling impulses are impressed uponsaid cable. v

7. A circuit for direct current signaling impulses comprising a line orcable, a transmitting battery associated therewith, a high impedancespace discharge device through the output circuit of which current fromsaid battery may flow, a controlling element for controlling the amountof current flow through the output circuit of said discharge space, anda signal key or circuit making and breaking device substantially freefrom contact chatter conductively in circuit with said controlling meansfor impressing the battery potential upon the control element andtransmitting signaling impulses from the output circuit of the spacedischarge device to the line without substantial change in frequency.

8. The'combination with a cable or line,

of a local source of transmittin potential connected With said cable orline, a resistance in shunt relation to said line with respect to saidsource of potential, a high impedance space discharge device in circuitwith said source of potential and said resistance, a control element forcontrolling the space discharge current, and a signaling key or circuitmaking and breaking device substantially free from contact chatter forcontrolling said control element. o

9. The combination with a signaling line or cable having largedistributed electrostatic capacity, of a local source of transmittingpotential, means having negligible reactance at signaling frequenciesassociating said source with said line or cable. a high impedance spacedischarge device for controlling current flow from said source andhaving an anode, a cathode and an impedance control element, and a keyor circuit making and breaking device substantially free from contactchatter controlling said im edance control element.

10. The combination with a signaling conductor or line having largedistributed electrostatic capacity, of a source of direct potential forimpressing direct current impulses on said line or cable, high impedancespace discharge means for controlling flow of current from said sourceto said cable,- and a signaling key or c1rcu1t makmg and breaking devicerelatively free from contact chatter for impressing positive impulseswhen in one position upon said line or cable and negative impulses whenin a second position.

11. Terminal signaling apparatus for a cable or line for impressingthereupon at t any instant potential of one of at least'two operatingvalues, whereby signaling impulses of either polarity and in any desiredmeans potential of one of at least two operating values and u on theother of said control means potentlal of another of said last-mentionedoperating values. v

12. A signaling system comprising a line, a pair of space dischargerelays associated with said llne, means adapted when operatedin onemanner to render one of said relays operative for transmitting directcurrent telegraph signals of a certain character over said line and whenoperated in a different manner to render the other of said relaysoperative for transmitting over said line direct current telegraphsignals of "a different character.

13. Asignaling system comprising aline, a first and a second spacedischarge tube for applying potentials of different polaritles to saidline, and means for rendering one or the other of said space dischargetubes operative for transmitting direct current telegraph signals oversaid line.

14. A signalin system comprising a line, a pair of space discharge tubeseach having a control electrode, a sourceof signaling potential, andmeans operative for conductively connecting said source of potentialwith the control electrode of one or the rther of said tubes forrendering such tube operative for transmitting direct current telegrziphsignals over said line.

15. signaling system, comprising a line, two repeaters of the audiontype, a source of signaling potential, a transmitting key operative forassociating said source of potential with either of said repeaters forren dering said associated repeater operative for transmitting directcurrent nals over said line.

16. In a signaling s'ystem,alineconductor, a symmetrical circuitarrangement comprising a pair of repeaters of the audion type, a sourceof signaling potential, and means for're'ndering one or the other ofsaid res peaters operative for transmitting over said line directcurrent impulses of equal intensity and Wave form.

17. In a signaling system, a line conductor, a pair of repeaters of theaudion type, a source of signaling potential, means for associating saidsource of potential with either of said repeaters for rendering saidrepeaters operative for the transmission of signals over saidline,.consisting of ,both positive and negative direct current impulsesof equal'intensity and wave form.

v 18. In a submarine signaling system, a.

telegraph sigline conductor, apair, of vacuum tubes each" having afilament, a control electrode and a plate electrode, means for normallyrendermg said tubes inoperative by maintaining each grid electrodenegative with respect to corresponding filament, a source of Sig? nalingpotential adapted to be connected with the control electrode of eitherof said,

tubes, a ke' for rendering one or the other of such tu es operative byconnecting said source of potential with said control electrode thereoffor the transmission of desired signalsx g 19. A signaling systemcomprising a line, twosimilar electric discharge devices, eacl1containing control electrodes, and oppositely associated-with said line,and means whereby directcurrent telegraph signals applied to the controlelectrodes renders one of said devices operative for transmittingsignals of one sign to the line, and the other responsive to thetransmitting signals of the opposite sign.

20. A signaling system comprising an electrically long signaling.conductor, a first and a second vacuum tube conductively connected tosaid line for applying potentials of different polarities thereto, and akey effective in two positions for rendering one or the other of saidtubes operative for transmitting direct current telegraph signals oversaid line. g

In witness whereof, I hereunto subscribe, my name this 23rd day ofDecember A. D., 1919.

OLIVER E. BUCKLEY.

